True or False Pope? Refuting Sedevacantism and other Modern Errors, by John Salza and Robert Siscoe, is a book regarded by many as the Summa and final word against Sedevacantism.
I have heard a lot about this book and here is why I am not going to read it.
Although I still have not definitively crossed that Rubicon, I maintain that there is a strong incentive to believe that Francis may have lost the Faith, and if so he would not be a pope.
How can the authors claim to refute the possibility of Sedevacantism when it is clear to me that I can make a personal decision that I no longer believe that someone professes the Catholic Faith? Why should I read 700 page book designed to show that there is no point in using my own mind to come to such a conclusion, or that my personal beliefs don't matter.
God has endowed us with memory, intellect and will. Don't I have a right to form my own personal beliefs using these means, otherwise why has He endowed us with these faculties?
I can make use of our God-given faculties of thought, reason and logic. [Intellect.]
I can make use of a study of what constitutes the Catholic Faith. [Memory.]
I can make use of my free will, in union with the Will of God. [Will.]
I can make us of prayer, especially Mary's Rosary.
I can make use of a properly formed Catholic conscience.
I can make use of my Sensus Catholicus.
I can make use of basic common sense: if it walks like a duck....
If the use of the above means causes me to no longer believe that Francis professes the Roman Catholic Faith, then I must conclude that he cannot be a true pope, since Our Lord promised Peter that his Faith would not fail him. It's really that simple.
But no - some will say that we must have a visible Church with jurisdiction. But I ask, is the Church since the Vatican II Council undergoing the Passion of Christ as many are now saying? Is not Holy Saturday a part of that event? On that day, there was no longer a visible Christ, there was no jurisdiction, all we had for certain was the perfect Faith of His Mother, Mary.
Is it not possible that the election of Pope John XXIII was invalid (theories abound), thus leading to a line of false popes? Is it not possible that Modernists hijacked the Council documents such that a counterfeit Church was created? The true Church was designed and created by Jesus Christ, and the nature of the Church is to "Go into the whole world and proclaim the gospel to every creature" (Mk. 16:15). But Karol Wojtyla admitted in Sign of Contradiction, "... the Church succeeded, during the Second Vatican Council, in re-defining her own nature." What a telling confession! Vatican II redefined what Christ established, creating a Church which replaces proselytism with dialog, conversion with shared prayer, and exempts today's Jews from having to except Jesus as savior.
Ironically the book True or False Pope? which is designed to refute Sedevacantism, might end up convincing Catholics to remain loyal to a false Sedevacantist Church and pope.
(In addition to what is mentioned in the above post, on their website for the book the authors resort to ad hominem personal attacks and mockery towards those who disagree with them, which indicates that the authors are not completely objective scholars.)